Cinema is a place of weird transactions. Filmgoers part with dozens of pounds for the pleasure of eyeballing actors who have parted with dozens of pounds. Matthew McConaughey lost nearly 50 for Dallas Buyers Club. He has since won a Golden Globe and is a frontline Oscar contender.

McConaughey goes for broke, which is the way brave film actors in Hollywood get rich. He looks like an anorexic vulture; he delivers lines as if they are peeled from his drying voice. He is terrifically good – as good as in his cameo in The Wolf of Wall Street – as the truth-based Texas homophobe and electrician who helped transform HIV treatment in the US. “Truth-based”, mind, should be taken warily. Friends of the late Ron Woodroof, who died from Aids-related illnesses in 1992, six years later than doctors had first predicted, denied he hated gay people. Some friends claimed he was gay himself.

How did Woodroof make his breakthrough and conduct his campaign? By spurning hospital-and-Food-and-Drug-Administration-approved medication and starting his own dispensing co-operative. He argued, sometimes in court, that the FDA was in the pay of Big Pharma, pushing its own dope, especially excess-dosage AZT. Meanwhile drugs lauded in other lands, including Interferon, were off the map in the US. So he got on his horse, flew to those distant lands – call his horse Pegasus – and smuggled the stuff in, sometimes disguised behind a clerical dog collar.

The medical maladministration scandal and maverick America’s response were the subject of a recent docu-feature, How to Survive a Plague. This film’s human drama is given more simple-minded, straight-line bravura. “Boo!” says the movie to the whitecoats who mis-prescribed in the name of civil obedience. “Hurrah!” it says for the cowboys led by one-time rodeo amateur Woodroof, a rabble-rouser whose rabbit habits with the ladies – at least in this version – got him the disease. The played-up machismo of McConaughey’s hero ensures a lot of “bigot repents” mileage when the homophobe must share office space with the likes of florid transvestite Rayon, played by Jared Leto as if he wants the junior Oscar to McConaughey’s senior one.

Almost everyone overacts; almost everything is over-spelled. The lighting, photography and script are no better than they should be. It would be a TV problem-of-the-week movie without McConaughey’s skill in combining intelligence with pizzazz. Extraordinarily, this is the actor’s second coming. He was proclaimed a young star in the 1990s, then burned out. For a while he was a derided supernova in romcoms. Now he is the wild card in the Hollywood casting pack for over-forties. Audiences wanting the unexpected know where to expect it.